Investigating the microstructures and properties of Mg‐Al LDH film‐coated Mg‐Li alloy: Effect of hydrothermal temperature

Abstract

Magnesia-alumina layered double hydroxide (Mg-Al LDH) films grown in situ on LA43M magnesium-lithium (Mg-Li) alloy were synthesized utilizing the hydrothermal method. Scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and X-ray diffraction (XRD) were used to characterize the surface morphologies, composition, and phase of the Mg-Al films. The corrosion resistance of the Mg-Al films was estimated via immersion experiment and hydrogen evolution test, and the tribological properties were investigated using tribological wear tests. The results showed that the thickness of the Mg-Al LDH film enhanced, and the size of the LDH sheets increased as the hydrothermal temperature raised, resulting in the improvement of the corrosion and wear resistance. When the hydrothermal temperature reached 110 • C, interlayer anions were loaded the most, and the film achieved the optimal thickness. The Mg-Al LDH film had the optimum corrosion resistance and tribological properties. At this point, the weight loss of the film was 1.3560 mg⋅cm -2 , and the average friction coefficient was .149. It demonstrated that synthesizing Mg-Al LDH at a hydrothermal temperature of 110 • C was an effective approach to improve the corrosion resistance of LA43M.

Enhanced corrosion resistance of layered double hydroxides/steam coating composite coating prepared by the hydrothermal method on LA43M magnesium–lithium alloy substrates

“…Although there were a few corrosion pits and partial peeling on the surface of the LDH/SC composite coating, a large number of LDH structures still exists, which still provides an effective barrier protection to the substrate. 23 In particular, the LDH/SC-100 • C (Figure 10E) composite coating is similar to the coating before immersion, and there are no evident cracks, indicating that its corrosion resistance reaches the highest point compared to other samples. The EDS mapping results after corrosion showed TA B L E 1 Tafel fitting results of potentiodynamic polarization curves in Figure 8.…”

“…In comparison, the LDH/SC composite coating was partially corroded and their surface remains relatively stable. Although there were a few corrosion pits and partial peeling on the surface of the LDH/SC composite coating, a large number of LDH structures still exists, which still provides an effective barrier protection to the substrate 23 . In particular, the LDH/SC‐100°C (Figure 10E) composite coating is similar to the coating before immersion, and there are no evident cracks, indicating that its corrosion resistance reaches the highest point compared to other samples.…”

Effects of Ti ion deposition on corrosion resistance of WE43 alloy

“…TiO 2 is inert and would not be corroded in the chloride solutions. In addition, Ti will adsorb Cl − in SBF solution to form a soluble chlorocomplex of titanium, and [TiCl 6 ] 2− ion hydrolyses forming the TiO 2 passive film 37 . The results of hydrolysis of titanium chloride in aqueous solution are as follows: $$$$\begin{equation} {\rm Ti} \to {\left[ {{\rm TiC}{l}_6} \right]}^{2 - }\mathop \Leftrightarrow \limits^{2{\rm H}_2{\rm O}} {\rm Ti}{\rm O}_2 + 6{\rm C}{l}^ - + 4{\rm H}^ + .\end{equation}$$$$…”

“…In addition, Ti will adsorb Cl − in SBF solution to form a soluble chlorocomplex of titanium, and [TiCl 6 ] 2− ion hydrolyses forming the TiO 2 passive film. 37 The results of hydrolysis of titanium chloride in aqueous solution are as follows:…”

A comparative study and optimization of corrosion resistance of Mg–Al layered double hydroxides films at different hydrothermal temperatures on LA103Z Mg–Li alloy

“…[6][7][8] Improved magnesium alloy corrosion resistance is, therefore, necessary immediately. Several anticorrosion approaches for Mg alloys have been established so far, including organic coating, [9][10][11] chemical conversion film, [12][13][14] micro-arc oxidation, [15,16] layered double hydroxide (LDH), [17] electroplating and chemical plating. [18][19][20] LDH has caught the attention of researchers for its potential in the field of corrosion protection of magnesium alloys due to its unique structure, which leads to excellent properties of adjustable organization, controlled chemical composition, interlayer ion exchange, and selfhealing properties.…”